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MRSA electron micrograph

MRSA Electron Micrograph

Methicillin Resistant Staphylococcus Aureus (MRSA)

What is Staphylococcus aureus?

Staphylococcus aureus, otherwise known as "Staph.," is a very common type of bacteria (or germ). Up to half of all people carry Staph on their skin and in other areas of the body. In most of these people, Staph lives harmlessly on the body. But Staph sometimes does cause actual infections. Most of these Staph infections are minor skin infections. Less commonly, Staph may go inside the body and cause more serious infections.

What are the symptoms of a S. aureus or MRSA skin infection?

Signs of a skin infection include redness, warmth, swelling, and tenderness of the skin. Some people with MRSA might think they have a "spider bite." For most people, it isn't serious. Others may develop boils, blisters, pustules or abscesses. The infection can cause a fever and/or chills. People with fever and/or chills should see their health-care provider. Click here for pictures of common MRSA infections.

What are MRSA, community-associated MRSA, and healthcare-associated MRSA?

In the 1960s some Staph gained resistance to an antibiotic, a type of medicine used to treat infections, called methicillin. "Resistance" means that an antibiotic no longer works against the bacteria. Resistant Staph are now called methicillin-resistant staphylococcus aureus, or "MRSA" (pronounced MER-SAH). As with ordinary Staph, some people carry MRSA on their skin without developing infections. Also, MRSA may also cause the same kinds of infection as ordinary Staph does. The main difference is that MRSA should be treated with different kinds of antibiotics than ordinary Staph. Until the late 1990's, MRSA infections were mostly seen in people who had been in hospitals and other healthcare settings. That type of MRSA is called healthcare or hospital-associated-MRSA, or HA-MRSA. HA-MRSA is still an important problem. It is difficult to treat (often requiring intravenous antibiotics), often affects people who are ill with other diseases, and usually causes more serious infections.


Recently there have been more MRSA infections outside of hospitals or other healthcare settings. The type of MRSA that causes those infections is called community-associated MRSA, or CA-MRSA. CA-MRSA usually causes minor skin infections but it can cause severe infections, even in healthy people. It also requires treatment with different antibiotics, but it is much easier to treat than HA MRSA.

How is MRSA spread?

Staph, including CA-MRSA, is primarily spread when someone's skin comes in contact with the skin of someone who has Staph. That sort of skin-to-skin contact can happen when someone is playing sports, having sex, or doing other things. It can only be spread with skin-skin contact or skin-contaminated object contact. MRSA is not known to be spread through the air.

Who is at risk of getting MRSA?

Everyone is at risk of getting MRSA. In general, the factors that make people more susceptible to MRSA infections are the 5 "Cs":


  • Frequent skin-to-skin contact
  • Compromised skin (i.e., cuts or abrasions)
  • Contaminated items and surfaces
  • Crowding
  • Lack of cleanliness.

Can I get MRSA at the gym?

While MRSA is primarily transmitted by skin-to-skin contact, there have been reported cases of transmission from environmental surfaces or equipment. To prevent this, wash hands before and after use, use a towel or clothing as a barrier between surfaces (such as exercise equipment or sauna benches) and bare skin, and keep wounds dry and covered.


Are HIV-infected people at greater risk of getting MRSA?

There is some evidence that people with weakened immune systems, including those with HIV infection, might be at higher risk of getting MRSA. Plus, when people with weakened immune systems do get MRSA infections, the infections tend to be more serious. Click here for more information.


Is MRSA a sexually transmitted disease (STD)?

Data do not exist to determine whether sex itself - anal, oral, or vaginal intercourse - spreads MRSA. But we do know that skin-to-skin contact, which occurs during sex, can spread MRSA.  Therefore, wearing a condom is unlikely to prevent infection.

A study about CA-MRSA in San Francisco was published in a medical journal in January 2008. That study article reported that multi-drug resistant MRSA infections were more common in gay men and other men who have sex with men in San Francisco. For this and other reasons, the article suggested that MRSA might be a sexually transmitted disease (STD). However, the study was not designed to answer the question of whether MRSA is in fact an STD. The media focused a lot of attention on this journal article at the time.


Are gay men or other men who have sex with men at higher risk of getting MRSA?

There is some evidence that gay men or other men who have sex with men are at higher risk of getting MRSA infections. The specific reason for this is not clearly understood, although we know that skin-to-skin contact during sex can spread MRSA. Data does not exist to answer the question of whether MRSA is transmitted through oral, anal, or vaginal intercourse. Read the CDC Statement on MRSA in Men who Have Sex with Men.

What should I do if I think I have an active MRSA infection?

If you notice any symptoms of a Staph infection, you should contact your health-care provider. You may need antibiotics or other treatment. Your healthcare provider will discuss treatment with you. Do not try to treat yourself. Whenever antibiotics are prescribed, take all of the medication even if you think the infection has gone away. This will help prevent the Staph germ from becoming more resistant to antibiotics.

Should People with MRSA Infections be Prevented from Going to Public Places?

It is not necessary for people with MRSA to be excluded from attending schools, gyms, saunas, or other public places. Everyone, infected or not, should perform proper hygiene and keep wounds adequately covered. Institutions do not need to be closed for disinfection after a case of MRSA is identified. Click on the following links for more information on MRSA prevention in schools and athletic facilities.

After I've had an MRSA Infection, am I Immune?

Some people do get recurrent MRSA infections and we do not know why. Certain people carry MRSA on their skin and/or in their noses. These individuals are considered to be MRSA "carriers" and may be more likely to get infections. There is not enough data to recommend specific treatments that get rid of MRSA carriage. However, there may be some cases in which healthcare providers recommend use of topical antibiotic ointments, antibiotics, and/or special washes to reduce carriage.


How do I protect myself from getting and spreading MRSA?

Practice good hygiene:


  • Wash your hands frequently with soap and water. If soap is not available, use hand sanitizer instead.
  • Showering or washing after contact sports, gym use, or sex may reduce the risk of skin-to-skin transmission.
  • Keep wounds covered with clean, dry bandages.
  • Take antibiotics only as prescribed by a healthcare provider
  • Do not share personal items such as used towels, clothes, razors, or anything that makes contact with skin.
  • Clean and disinfect items that are shared before and after every use (athletic/workout equipment) with disinfectant or detergent. A list of products approved by the Environmental Protection Agency that are effective against MRSA is available here. These products should be used only as directed.
  • Use lotion to keep skin moist; damaged skin can provide an opening for infection.

Additional Information

General Public


Schools and Parents

Health Care Providers


Clinician Reporting


Athletic Facilities, Athletes, and Athletic Teams




Correctional Facilities


San Francisco Surveillance Information

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